You know that the silly season is upon us when the foolish remarks of a fringe member of a fringe party are front-page news. Yet the use of the phrase “Bongo Bongo land” by the Ukip MEP, Godfrey Bloom, was more than a lapse of taste and judgment. It raises important questions about political language in general and the prospects of Ukip in particular.

The rise of Nigel Farage’s party has been one of the main political trends of the past year, prompting fears in Tory ranks of an organic split on the Right. The Ukip leader insists that he should be included in the 2015 leaders’ debates. His party is expected to do well, perhaps even to win, next year’s European elections. So what Ukip’s senior representatives say matters rather more than it used to. The controversy stirred by the MEP for Yorkshire and North Lincolnshire deserves its media prominence.

In his recorded declaration to a group of activists in the West Midlands, Bloom said: “How we can possibly be giving £1 billion a month, when we’re in this sort of debt, to Bongo Bongo land is completely beyond me. To buy Ray-Ban sunglasses, apartments in Paris, Ferraris and all the rest of it that goes with most of the foreign aid.” For this, he was forced by his party’s leadership to issue a barely there apology – but insisted on Channel 4 News that “I didn’t feel that I’d done anything wrong”.

In the same interview, Bloom claimed that his candour had “started a national debate” on international development. But the opposite is true. I happen to support the ring-fencing of the aid budget, and particularly recommend the writings of Prof Paul Collier, the Oxford economist, who advised the Prime Minister on the G8 and has become a centre-Right guru on development issues. I also see that – especially in times of domestic austerity – there is a legitimate counter-argument and a discussion to be had.

But using a term like “Bongo Bongo land” is not an invitation to a debate. It is an ugly declaration of bigoted certainty, crass xenophobia dressed up as pub banter. It is so roundly dismissive of the countries that receive aid – many of them scarred by famine and millennial poverty – that one wonders what sort of discussion Bloom could conceivably have had in mind.

Like a diplomat brandishing his immunity, the MEP also claimed that he was exempt from the criticisms levelled at him on the grounds that “I don’t do political correctness”. He insisted upon this in the way that a child might announce a parental letter letting him off PE or warning of a nut allergy: “Dear Mr Cameron, Godfrey has a sore head and will be unable to do Political Correctness today. Please allow him to stay with matron during all discussion of sub‑Saharan Africa…” etc.

If any phrase illustrates the importance of language and its accurate deployment in political discourse, it is “political correctness”. These two words once had real meaning, referring to a genuinely sinister bid, most potent in the Eighties and early Nineties, to purge US campuses of teachers who did not sign up to an ultra-Left approach to race, gender, sexuality and culture. The impact of this menacing phenomenon is beautifully memorialised in Philip Roth’s novel The Human Stain, David Mamet’s play Oleanna, and Allan Bloom’s The Closing of the American Mind.

A lesser strain swept through the town halls and local education authorities (LEAs) of this country in the Eighties, as the far Left, defeated at national level, took refuge in the municipalities. This bizarre hybrid of censorship and cultural relativism did immense damage in schools but was pushed into full retreat by the erosion of the LEAs — a long battle now in its final phase under Michael Gove’s successful captaincy.

“Political correctness”, in other words, is a phrase with very particular historical origins and significance. Unfortunately, it has been debauched by over-use to the point where it is almost meaningless – and it is to David Cameron’s credit that he said as much during his leadership campaign in 2005. It is not “politically correct” to stop children calling each other “spastic” or “gay” in the playground. It is not “politically correct” for schools and employers to offer (for instance) practising Muslims the opportunity to pray and, where possible, halal food. It is not “politically correct” to say that Little Black Sambo, published in 1899, is no longer an appropriate book for the classroom.

What is lazily dismissed as “political correctness” is often simple politeness, an example of our adaptive civilisation. This is a country of evolutionary change, successfully pluralist for millennia because of a national genius for good manners and peaceful coexistence. This is why Enoch Powell, so right about monetarism and the problems that membership of the Common Market would entail, was so wrong to predict, with Virgil, that the river would foam “with much blood”. We are an island people constantly modifying our composition and our relationship with the rest of the world. This is a capacity – patriotic rather than nationalist — that any true Conservative should celebrate.

It is often asserted that phrases like “Bongo Bongo land” only trouble a tiny Guardian-reading minority in Islington or those in the “Westminster bubble”, and that beyond these enclaves of liberal opinion such rugged language is not only accepted but celebrated. I do not believe such a sharp divide exists: the spectrum of opinion is much broader.

There may indeed be some who inwardly cheered Bloom’s choice of words. But there will be many – including, crucially, some who agree with his position on aid – who felt queasy at the use of such antediluvian language. There is an amorphous mass of floating voters, those who decide marginal seats, who are wary of any politician who presents bigotry as plain talking and seems unable to make his case without recourse to crude language.

Bloom claims that “it’s a generation thing”, as if he were a Chelsea Pensioner baffled by the world today. But he is only 63, born a year and a half after the Empire Windrush arrived at Tilbury with the first large contingent of West Indian immigrants; he grew up in a post-imperial, post-Suez world. Bloom is considerably younger than Keith Richards and Sir Paul McCartney. If he talks like a character from Rider Haggard, that is a matter of choice, not generational inevitability.

Ukip is presently a campaign body that does well in European elections because of PR, and in by-elections as a magnet for the protest vote previously mopped up by the Lib Dems. If Farage’s party is to become a force at Westminster, it has to attract more than a coalition of the outraged, the disenfranchised and anti‑Cameron defectors.

A political party is not a free-for-all. It is a disciplined organisation dedicated to the acquisition and retention of power. To a greater extent than has been acknowledged, this is a fork in the road for Farage. Is Bloom really the sort of candidate his party will be putting up next year and in the general election? Until he answers that question, we shall not know how great Farage’s ambitions truly are.